Hand Tools Archive

Re: Product Dev. & Some User Data

David Weaver
I had a couple of chisels in M4, but no plane irons. The chisels were good, but they still needed to be resharpened every once in a while. I couldn't really say for sure that they would provide any productivity improvement over japanese carbon steel chisels - probably not, especially when sharpening time is factored in. They're laminated and soft iron or mild steel on diamonds in a cast or steel plate is a disaster - cast and mild plates are the domain for tools that are all hardened material.

I sharpened my chisels on crystolon followed by a fine india followed by a hard arkansas. To my surprise, the crystolon did a good job grinding the bevels (I worked the back with a diamond plate - they are hollow, so it wasn't too difficult). The bevel side (since it's laminated) on a chisel isn't that much hardened material to cut, which may be why the crystolon did OK with it. The fine india and arkansas stone can't cut all of the stuff that's in it so they probably didn't do much, but I got the edge to the point that it looked good under a scope, at least reasonably good, and was past easily shaving hair.

But something about them didn't resonate.

I sent one of them to Rob Streeper in texas who was doing some (potentially inaccurate in some cases) testing of chisels and the one he tested was the hardest of all of the chisels he tested. 66 or 66.x hardness. I trust they would do well if you wanted to shave a transition on something where brass meets wood.

As far as the plane irons go, there are commercially made irons of M2 and M4 in japan, but it's not like you can stick them in a western plane. I have no idea how well they go over in japan. Earlier HSS tools were intended for site work and were relatively crude, but some of the planes with the irons in them now (the m4 types) are over $400, so they're not really site tools. Someone must like them.

Those are also laminated, but glued together rather than forged together. The back of the blade on those tools is made without sides on the hollow so that the user only ever sharpens a small strip at the tip of the iron.

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